1. Field of the Invention
The present invention is related to stringed instruments and, more particularly, is directed towards bridge and tuning mechanisms utilized with stringed instruments.
2. Description of the Related Art
In order for a stringed instrument to be in tune, the octave point of each string must be aligned with its corresponding octave fret which is located, for example, on the neck of an electric guitar or bass. The octave point of a string is defined by the overall resonant length of the string which is, in turn, defined by the distance between the cross-over point of the string at the nut and the cross-over point of the string at the bridge. As long as the distance between the cross-over points at the nut and the bridge remain constant, the resonant length of the string, and therefore its octave point, also remains constant.
In modern electric guitars, for example, it is realized that the height of each string relative to the neck of the instrument is a matter of personal taste, and many mechanisms have been introduced to permit the height of the strings to be varied as a user may desire. See, for example, U.S. Pat. No. 4,031,799 to Fender. This height adjustment is generally achieved by varying the spacing between the bridge and the body of the instrument by means of, for example, set screws which extend vertically through the bridge sections (also known as drums).
However, it is also known that adjusting the spacing between the bridge and the instrument body undesirably results in a change in the length of each string, which, as stated above, results in a change in the location of the octave point of the string. It has therefore been recognized that in order to maintain the string in tune, it is necessary simultaneously to adjust the lateral position of the bridge (and hence the cross-over point of the associated string) when adjustments are made to the height thereof. This is achieved by providing a plurality of bridge sections or drums which are individually laterally as well as vertically adjustable. See also, for example, U.S. Pat. Nos. 2,972,923; 3,290,980; and 3,427,916.
The individually adjustable bridge designs of the prior art are embodied by precision mechanisms which increase the cost of the stringed instrument but are nevertheless necessary to maintain the instrument in proper tune.
Double-stringed guitars are those provided with a plurality of pairs of strings. Each pair comprises two strings placed close together and played as one string tuned in an octave. The pair of strings produces a tone which cannot be achieved by an ordinary single-stringed instrument. See, for example, U.S. Pat. Nos. 1,721,710; 1,819,371; 3,269,247; and 3,344,698. In each of the double-stringed instruments described in the foregoing patents, one end of the strings are terminated on the body after passing over a bridge, and the other ends thereof are terminated by a plurality of tuning keys located on the head of the instrument after passing over a nut.
Recently, electric guitar manufacturers have marketed double-stringed electric guitars wherein one string of each pair of strings are tuned conventionally by tuning keys mounted on the head of the instrument, whereas the other string of each pair of strings extends across the bridge to be tuned by auxiliary tuning keys mounted to the body of the instrument, as exemplified by Model No. XL8 manufactured by Kramer Guitar Corporation, Inc. of Neptune, N.J. The more modern double-stringed guitars employ, as one would expect, a precision adjustable bridge mechanism (as discussed above) in order to maintain the strings in tune while permitting the musician to adjust the strings of the instrument to suit his taste.
While a double-stringed guitar is a nice adjunct to a musician's inventory of instruments, it is only suitable for certain songs and therefore represents a substantial additional investment. It would therefore be highly desirable if a device or kit could be provided, at relatively low cost, which would permit a musician to readily convert either his own or an older, used single-stringed instrument to a double-stringed instrument, and vice-versa, at will. Such a kit or device would clearly save the tremendous costs incident to purchasing a new double-stringed guitar as opposed to converting an existing, perhaps unused single-stringed guitar.
Such a conversion kit should also preferably be readily compatible with existing guitar designs, which would provide a ready market for the kit. The kit should include means for adding the extra strings and terminating the respective ends thereof in the head and body of the instrument over suitable nut and bridge assemblies, as well as means for tuning the added strings. Finally, the kit should incorporate an adjustable bridge assembly, for the reasons set forth above.
It is towards providing such a kit, and a novel component thereof, that the present invention is advanced.
U.S. Pat. Nos. 2,523,963 and 3,910,151 show guitars wherein the tuning keys are mounted to the body of the guitar, rather than to the neck. However, neither of the instruments shown in these patents are directed towards a double-stringed guitar, and neither suggests the unique combined bridge/tuning mechanism of the present invention as will be set forth in greater detail below.
U.S. Pat. Nos. 3,163,073 and 4,007,658 teach electric steel pedal guitars wherein the strings are mounted on pivotable levers which also contain the tuning keys. No means are provided, however, for an adjustable bridge mechanism since steel pedal guitars are played with a steel bar which, by its nature, does not require vertical or horizontal adjustment of the strings as with a hand-held electric guitar or similar stringed instrument.